netdev - [PATCH net-next v2 03/12] amd-xgbe: Remove use of comm

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Date:   Wed, 23 May 2018 11:38:29 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     netdev@...r.kernel.org
Cc:     David Miller <davem@...emloft.net>
Subject: [PATCH net-next v2 03/12] amd-xgbe: Remove use of comm_owned field

The comm_owned field can hide logic where double locking is attempted
and prevent multiple threads for the same device from accessing the
mutex properly.  Remove the comm_owned field and use the mutex API
exclusively for gaining ownership.  The current driver has been audited
and is obtaining communications ownership properly.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c |   16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index 123ceb0..05003be 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
@@ -327,8 +327,6 @@ struct xgbe_phy_data {
 
 	unsigned int mdio_addr;
 
-	unsigned int comm_owned;
-
 	/* SFP Support */
 	enum xgbe_sfp_comm sfp_comm;
 	unsigned int sfp_mux_address;
@@ -382,12 +380,6 @@ struct xgbe_phy_data {
 static int xgbe_phy_i2c_xfer(struct xgbe_prv_data *pdata,
 			     struct xgbe_i2c_op *i2c_op)
 {
-	struct xgbe_phy_data *phy_data = pdata->phy_data;
-
-	/* Be sure we own the bus */
-	if (WARN_ON(!phy_data->comm_owned))
-		return -EIO;
-
 	return pdata->i2c_if.i2c_xfer(pdata, i2c_op);
 }
 
@@ -549,10 +541,6 @@ static int xgbe_phy_sfp_get_mux(struct xgbe_prv_data *pdata)
 
 static void xgbe_phy_put_comm_ownership(struct xgbe_prv_data *pdata)
 {
-	struct xgbe_phy_data *phy_data = pdata->phy_data;
-
-	phy_data->comm_owned = 0;
-
 	mutex_unlock(&xgbe_phy_comm_lock);
 }
 
@@ -562,9 +550,6 @@ static int xgbe_phy_get_comm_ownership(struct xgbe_prv_data *pdata)
 	unsigned long timeout;
 	unsigned int mutex_id;
 
-	if (phy_data->comm_owned)
-		return 0;
-
 	/* The I2C and MDIO/GPIO bus is multiplexed between multiple devices,
 	 * the driver needs to take the software mutex and then the hardware
 	 * mutexes before being able to use the busses.
@@ -593,7 +578,6 @@ static int xgbe_phy_get_comm_ownership(struct xgbe_prv_data *pdata)
 		XP_IOWRITE(pdata, XP_I2C_MUTEX, mutex_id);
 		XP_IOWRITE(pdata, XP_MDIO_MUTEX, mutex_id);
 
-		phy_data->comm_owned = 1;
 		return 0;
 	}